Field
Embodiments of the present disclosure relate to a laundry treating apparatus.
Discussion of the Related Art
A conventional laundry treating apparatus includes a cabinet forming an exterior appearance, a tub mounted in the cabinet, a drum rotatably mounted in the tub to wash laundry held therein and a motor having a shaft fixed to the drum through the tub to rotate the drum.
According to the location of laundry loaded in the drum, the drum may be unbalanced when rotated (i.e., not keeping a dynamic balance).
Dynamic balance means a state where a centrifugal force or a moment made by the centrifugal force when a rotary body is rotated is 0 (zero) with respect to a rotation axis. A dynamic balance of a rigid body is maintained when the mass distribution is uniform with respect to a rotation axis.
Accordingly, it can be understood that dynamic balance of a laundry treating apparatus means a state where the mass distribution of laundry with respect to a shaft of a drum (i.e., a rotational axis) is in an allowable range, when a drum is rotated with laundry held therein (i.e., a state where the vibrations of the rotating drum are in an allowable range)
Meanwhile, a state where the dynamic balance is lost in a laundry treating apparatus (i.e., an unbalance state) means that mass distribution of laundry with respect to a shaft (rotational axis) is not uniform while a drum is rotated. The unbalance state may be generated when the laundry is not distributed uniformly.
When the drum rotates in the unbalance state vibration is generated. The vibration of the drum could be transferred to a tub or a cabinet, such that the transferred vibration might cause a noise problem in the laundry treating apparatus.
One of conventional laundry treating apparatuses includes a balancing unit for improving unbalance of a drum. Such balancing units provided in conventional laundry treating apparatuses may be fixed to a tub, with balls or liquid provided in a closed housing.
The rotation speed of the unbalanced drum is the highest when the laundry causing unbalance is passing the lowest point of a drum rotation locus and the rotation speed is the lowest when the laundry causing the unbalance is passing the highest point of the drum rotation locus.
Balls or liquid provided in a conventional balancing unit may be configured to move towards the lowest point of the drum rotation locus when the laundry causing the unbalance to move towards the highest point, to control the unbalance.
However, while the unbalance control system/method mentioned above is effective in a steady state where the vibration of the drum is within a preset range, the unbalance control is expected to be often present in a transient state (i.e., a transient vibration state) before the steady state.
Additionally, it is difficult to immediately improve the unbalance (i.e., to actively ease the unbalance) in the structure of the conventional balancing unit, when the unbalance is generated.